Potential-indicator



(No Model.) 3 Sheets-Sheet 1.

G. A. LINTNER.

POTENTIAL INDICATOR.

No. 495,225. Patented Apr. 11. 1893.

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(No Model.) 3 SheetsSheet 3.

G. A. LINTNER.

POTENTIAL INDICATOR. No. 495,225. Patented Apr. 11,- 1893.

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UNITED STATES PATENT OFFICE.

GEORGE A. LINTNER, OF MINNEAPOLIS, MINNESOTA.

POTENTIAL-INDICATOR.

SPECIFICATION forming part of Letters Patent No. 495,225, dated April 11, 1893. Application filed November 17, 1892. Serial No. 452,270. (No model.)

To all whom it may concern:

Be it known that I, GEORGE A. LINTNER, of Minneapolis, in the county of Hennepin and State of Minnesota, have invented certain new and useful Improvements in Potential- Indicators, of which the following is a specification.

My invention relates to means for accu-- rately indicating or measuring the potential on one or more electric lines or circuits, and for instantly calling attention to an increase or a decrease of potential thereon, to the end that the inequality may be remedied before serious damage can be done to translating devices upon the working circuit, such as electric lamps or motors.

The object of theinvention is to provide an instrument calculated for such service and which will surpass in cheapness, simplicity, accuracy, and reliability any of the similar devices now in use.

My invention consists in the combination with a source of electrical energy and a main circuit of a solenoid of high resistance included in said circuit, a core therefor, a pointer arranged to be operated thereby, contacts in position to be singly engaged by said pointer, signal lamps included in circuit between said contacts, an audible signal arranged in a circuit extending from a point between said lamps to a connection with said pointer and said circuit includinga source of electrical energy whereby an excess or a fall of potential in the main line is indicated by the ringing of a bell or other audible signal and the lighting of one or the other of the lamps.

The invention consists further in adapting the single set of signal lamps and the bell for use with two or more independent dynamo circuits; and furtherin certain constructions and combinations all as hereinafter described and particularly pointed out in the claims.

The invention will be more readily understood by reference to the accompanying drawings, forming a part of this specification, in which:-

Figure 1 shows a potential indicator and signal embodying my invention. Fig. 2 is a diagrammatic view showing the circuits of the potential indicator and also showing the manner of adapting the same for use upon independent dynamo circuits. Fig. 3 is a diagram of the circuits which I employ when the indicator is used upon a single working circuit. Fig. 4 is a detailed View of a modified form of my indicator.

As shown in the drawings, 2 represents a curved solenoid of high resistance and 3 the core or armature adapted to be drawn into the same. This core is attached rigidly to the free end of the arm 4, which arm is pivoted on the stud 5 and bears the pointer 6. The arm, pointer and core may be suitablybalanced by a weight 7.

Instruments of this class are adapted for use upon lines, the normal potential of which is known. I provide contact points 8 and 9 therefor on opposite sides of the lower end of the pointer and adjust them so as to have only a small space between them for the vibration of the pointer. A rise of potential slightly in excess of the normal will cause the core to be drawn somewhat farther into the solenoid and the pointer to engage the contact post 8 while a diminished pressure on the line would result in the receding of the core therefrormand the engagement of the pointer with the opposite or negative post 9. The solenoid 2 is included in the main circuit 10, extending be tween the terminals 11 and 12 upon the dynamo.

l3 and 14 represent two lamps preferably of different colors, the lighting of the lamp 13 indicates a falling potential, While the illuminating of the lamp leindicates a high potential. These lamps are included in series in the short line 15, the terminals of which are the separated posts 8 and 9, the circuit consequently being normally open and the lamps dark.

From a point 16 between the two lamps a leg 17 extends to one side of the main circuit 10. From the other side of the dynamo circuit a line 18 extends to the pivot post 5 of the pointer to conduct current thereto. In this line is included an electromagnetic bell 19, adapted to ring when the circuit is closed by the engagement of the pointer with either one of the posts 8 or 9 and from thence circuit would be completed through one side of the line 15, thence through one of the lamps to the leg 17 and the other terminal of the dynamo. In place of the above connections I may substitute those shown in Fig. 3. Here the solenoid, the pointer, core, the contact points, and the high and low potential lamps all correspond to those of Fig. 2 and the solenoid is similarly connected in the main circuit 20. Short lines 21 and 22 extend from the contact posts 8 and 9 respectively to connections with opposite limbs of said circuit 20. The two lamps are arranged in series in the line 23 which joins the opposite sides of the circuit. From a connection between the lamps the line 24 extends through the electro-magnetic bell 19 and from thence to an electrical connection with the pointer 6. It will be seen that a decrease of potential upon the line 20 will cause the pointer 6 to move against the post 8 whereupon circuit will be made through the pointer, the line 22, thence over the branch of the main circuit to the dynamo; from the opposite pole of the dynamo circuit may be traced through the opposite limb of the main circuit 20 and to the point of juncture with the line 23, from thence sufficient current will flow to the low potential lamp 25, and after passing through said lamp pass out over the line 24, through the bell and back to the pointer. The swaying of the pointer in the opposite direction to make contact with the contact post 8 results in the lighting of the high potential lamp 26 and the sounding of the bell or other audible alarm.

The circuits above described are substantially the same but I prefer to employ the first in as much as the signal lamps and contact points thereof may be so connected with another solenoid, pointer, &c., as to dispense with the use of a second pair of signal lamps in connection with the second solenoid. Such an arrangement is clearly indicated in Fig. 2, wherein 27 indicates a solenoid similar to 2 and equipped with acurved core 28, swinging arm 29, and a pointer 30. At the lower end of the pointer and on opposite sides thereof are contact posts 31 and 32 corresponding to-8 and'9. The post 31 is connected with post 8 by a short cross line 33 and the post 32 is connected with the post 9 by a short line 34. From the pointer 30 a line 35 extends to a point on the line 18 between the bell 19 and thepointer 6. The other connectionsto the solenoid may consist in a third wire 37 of a three wire system and a neutral wire connection 38 or instead the solenoid may be connected between the terminals of another dynamo 39.

It will be observed that all the current for energizing the signals is derived from one circuit only,namely the circuit 10. Suppose the pointer 6 to be standing in its normal position entirely disengaged from its contact posts 8 and 9 and then suppose a high potential to be present upon the working circuit which nected to the post 8 from whence current would flow through the lamp 14, thence through the leg 17 and to one terminal 11 of the dynamo. From the opposite terminal current would pass to the line 18, thence through the bell and from the opposite side of the bell through the line 35 to the pointer 30 bearing upon the post 31. A low potential upon the second line would deflect the pointer 30 against the post 32 and result in the lighting of the low potential lamp 13 and the sounding of the alarm bell. After finding the high potential lamp burning it is the duty of the attendant to determine by test which of the two lines is at fault. In case the potential on one main circuit should be high and on the other low both of the lamps 13 and 14 would be lighted and the bell sounded with double such energy so as to attract attention by the increased volume or sound therefrom.

It occasionally happens that the machine from which the current is derived for energizing the signals is shut down while the other lines continue to carry current. In

order that my potential indicator and signal will be seen that the contact points or blocks 8 and 9 are adjustable upon the'curved rods .43 and 44 respectively to render the device capable of use upon a circuit the normal potential of which is subject to predetermined changes which determine the relative positions of the pointers. A further advantage is that these contact points may be removed to the outer ends of the rods 43 and 44 thereby allowing the needle -or pointer to swing freely and permitting the employment of the device as a simple volt meter. For this purpose and to assist in the accurate and easy adjustment of the contact points I preferably provide a graduated scale card 45 beneath each of the volt meters shown upon the board 46. It is desirable that the pointer should be at once sensitive to any change of potential and at the same time sufficiently steady to prevent its being continuously vibrated between the contact points. Neither of these qualities are prominent in a single core solenoid wherein it is well known that the attraction weakens as the core progresses beyond the center within the solenoid thus rendering the action of the pointer attached to the core less sensitive to variations of potential be yond the normal. I am enabled to overcome this disadvantage by the employment of a dummy-core 47 entering the end of the solenoid opposite the core 3 and arranged to swing with the arm 48 journaled on the stud 5 but not connected with the arm at. Lugs 49 project over the two arms and a tension-spring 50 is arranged at their upper ends and made adjustable by means of the thumb-nut 52. A stop 53 is preferably provided beneath the arm 48 to prevent the core 47 from entering the solenoid so far as to come in contact with the inner end of the core 3 in which case the attraction between the cores which are obviously of opposite poles would be so great as to prevent their easy separation. The advantage gained by this construction is due to the fact that the attraction of the oppositely polarized cores for one another as they approach increases inversely with the square of the distance rendering them responsive to very slight changes of potential. This added to the constantly accelerated attraction of the solenoid proper (the cores never reach the center thereof) gives to the instrument a very high degree of delicacy and secures wide range of movement for the slightest change of potential within the safe working limits of the constant potential system upon which the instrument is used.

As a precaution against a possible failure of contact between the pointer and one of the contact blocks, due to oxidation or other defeet, I may provide a pointer upon each of the swing arms as represented in Fig. 4 by the pointers 6 and 60, attached to the arms 4 and 48 respectively; between the lower ends thereof is a double contact point with which both pointers will engage when the cores are drawn into the solenoid by an increased pressure on the line. Upon a movement in the opposite direction the pointers would engage the outside blocks 62 and 63. The blocks are preferably made adjustable on the curved guides or rods 64 and 65 and a graduated scale card 66 is provided beneath the pointers as an aid to the proper adjustment of the blocks.

For convenience in manufacture the solenoid is made of two or more small bobbins 55 as shown in Fig. 1, the same being slipped over a curved sleeve or sheaf and having their windings connected in series. The high and low potential colored lamps 13 and 14 are secured upon the board 46 in suitable sockets provided thereon and for the sake of symmetry the bell is arranged between the lamps. A glass cover is ordinarily provided over the two indicators on the lower part of the board. Care should be taken to have the cross section of the cores suificiently large to prevent their saturation. If this is done the magnetism ot the cores will be accelerated by a rise of potential as well as the strength of the magnetic field of the solenoid. One of the cores may be stationary though I prefer the above described arrangement.

Having thus described my invention, I claim as new and desire to secure by Letters Patent- 1. The combination, with a solenoid, of a main circuit including the same, a core or armature for said solenoid a pointer arranged to be operated by the movement of said core, contact points or blocks to be engaged separately by said pointer, translating devices included in series between said contact points and consequently in a normally open circuit, an electric audible signal included in a connection extending from a point between said translating devices to said pointer, and a source of electrical energy included in said connection, substantially as and for the purpose specified.

2. The combination, in a potential indicator, of a curved solenoid included in aworking circuit, with a swinging curved core therefor, a pointer to be operated by the movement of said core, a contact point arranged 'on each side of said pointer and to be engaged thereby, two incandescent lamps included in series between said contact points, an electromagnetic bell, a connection extending between said lamps to said pointer and including said bell, and a source of electrical energy also included in said connection whereby a variation of potential on the circuit of the solenoid will result in the ringing of the bell and the illumination of one of said lamps, substantially as and for the purpose set forth.

3. The combination, with a main circuit and a source of electrical energy, of asolenoid included in said circuit, a core for said solenoid, a pointer connected with said core, contact points to be engaged by said pointer, a connection between said pointer and one limb of said circuit, an audible signal included in said connection, signal lamps included in series betweeen said contact points, and a connection from between said lamps to the other limb of said circuit, substantially as and for the purpose set forth.

at. The combination, in a potential indicator, of two or more main circuits, a solenoid included in each circuit, a core provided with a pointer for each solenoid, two contacts for each pointer, the corresponding contacts of said pointers being electrically connected, two translating devices included in series between one pair of said contacts, a connection extending from a point between said devices to the particular pointer adapted to engage said pair of contacts, and an audible electric alarm, and a source of electricity both included in said connection whereby a variation of potential on one or more of said main circuits is indicated by the sounding of said alarm and the illumination of one or both of said lamps, substantially as described.

5. The combination, with two or more main circuits of a solenoid for each, the core of each solenoid, pointers to be operated thereby, a pair of contact points or blocks for each pointer to be engaged by said cores, two electric lamps of different colors arranged in series between the contact points of one pair, a

connection extendingfrom between said lamps to one limb of one of said main circuits, an electric bell and a connection including the same and extending from said pointer to the other limb of said circuit, substantially as and for the purpose set forth.

6. The combination, with a solenoid, of two cores extending into opposite ends of said solenoid, a pointer arranged to be operated by the movement of one of said cores and a graduated scale across which said pointer operates, substantially as described and for the purpose set forth.

7. The combination, with a curved solenoid, of a main circuit including the same, a pivot, two arms independently pivoted thereon, a curved core secured upon each arm, said cores extending into opposite ends of said solenoid, a pointer attached to one of said arms, contact points arranged on opposite sides of said pointer, translating devices included between said contacts, an electrical bell, a connection extending from between said translating devices to said pointer and including both said bell and a source of electrical energy, substantially as described.

8. The combination, with a main circuit, of a curved solenoid included therein, the curved core, the swinging arm whereon said core is fixed, a pointer provided in connection with said arm, the curved rods 43 and 44, the slidable contact blocks 8 and 9 arranged thereon to be engaged by said pointer, a reading scale 45, signal lamps included between said contacts, a connection extending from a point between said lamps to said pointer, and an electric bell and asource of electricity both included in said connection, substantially as described and for the purpose specified.

9. The combination,of the curved solenoid composed of several bobbins of wire connected in series, with a pivot post 5, two arms journaled thereon, the curved cores attached to said arms and projecting into opposite ends of said solenoid, lugs 49 on said arms and an adjustable spring arranged between said lugs substantially as described and for the purpose set forth.

10. The combination, with a solenoid, of two cores arranged to enter opposite ends of the same, a pointer arranged in connection with each, electrically connected contacts arranged between the free ends of said pointers, a contact arranged opposite the outer side of each pointer, said contacts being connected and signal circuits connected with said contacts, substantially as described.

11. The combination with the solenoid, of two cores to enter opposite end-s thereof, swinging arms 4 and 48 whereto the said cores are attached, pointers 6 and 60 attached to said arms 4 and 48, respectively, a double contact 61 provided between the free ends of said pointers, the contacts 62 and 63 to engage the outer sides thereof, and said contacts being adjustable, substantially as and for the purpose set forth.

In testimony whereof I have hereunto set my hand this 9th day of November, 1892.

GEORGE A. LINTNER.

In presence of O. G. HAWLEY, FRED S. LYON. 

